Textures are inside the model
You need to enable Backface Culling in the material settings. It is the extra geometry for creating an outline blocking the view.



You can build a custom toon shader. Here is one:



This is for EEVEE only.



If you want you can watch some tutorials on Non-PBR shading. For example https://www.youtube.com/watch?v=E3zHGD8V2IY or https://www.youtube.com/watch?v=dCF29s2FRsQ